Pass enable_topchrome_md as a grit define

Pass enable_topchrome_md as a grit define

Specify enable_topchrome_md as a grit define, which
will be used to specify new asset IDs which
are only applicable to platforms affected by
the material design refresh in browser top chrome.

BUG=520992
TEST=none

Committed: https://crrev.com/01b7e6102e67d35eb46060f05901f62955ca6e62
Cr-Commit-Position: refs/heads/master@{#343415}

[tdanderson, 2015-08-14 15:50:47]

tdanderson@chromium.org changed reviewers:
+ scottmg@chromium.org

[tdanderson, 2015-08-14 15:50:47]

Scott, can you please take a look?

[scottmg, 2015-08-14 16:01:36]

lgtm

[tdanderson, 2015-08-14 16:05:55]

The CQ bit was checked by tdanderson@chromium.org

[commit-bot: I haz the power, 2015-08-14 16:06:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1299433002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1299433002/1

[commit-bot: I haz the power, 2015-08-14 16:58:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-14 16:58:46]

Patchset 1 (id:??) landed as
https://crrev.com/01b7e6102e67d35eb46060f05901f62955ca6e62
Cr-Commit-Position: refs/heads/master@{#343415}